1. Field of the Invention
The present invention pertains to eye surgery and, in particular, cataract: surgery and surgical knife blades and methods for making sutureless incisions in the eye.
2. Description of the Prior Art
Various surgical procedures of the eye require that incisions be made in the eye to gain access to the anterior chamber as well as other parts of t-he eye. In cataract surgery, an incision is made in the eye to gain access to a cataractous natural lens allowing removal of the cataractous lens and implantation of an intraocular lens implant. One popular technique, i.e. the extracapsular technique, for cataract surgery involves making a plunge cut or one plane incision through the scleral corneal junction of the eye to enter the anterior chamber allowing an instrument, such as a phacoemulsifier, for removing the cataractous lens to be introduced at the anterior chamber through the incision. Once the cataractous lens has been removed with the instrument, an intraocular lens implant is inserted through the incision, which is enlarged as necessary to receive the implant, and guided into the position previously occupied by the natural lens. Upon implantation of the intraocular lens implant, the incision is closed with sutures. Suturing the corneal incision can be very tedious and time consuming due to the extremely small size of the sutures, and the sutures increase the occurrence of post-operative astigmatism, patient discomfort and foreign body sensation as well as other complications of surgery.
Sutureless incisions, also known as corneal valve incisions, represent a latest significant advance in intraocular surgery and, in particular, cataract surgery. Sutureless incisions, wherein the positive pressure of the eye maintains the incisions closed and the tissue approximated for healing without the need for sutures, has numerous advantages over incisions requiring suture closure including reduction of post-operative astigmatism, better maintenance of the anterior chamber, avoidance of foreign body sensation, enhanced comfort through the post-operative period and simplification of surgical procedures of the eye. U.S. Pat. No. 5,098,438 to Siepser is illustrative of surgical knife blades and methods for making sutureless incisions in intraocular surgery. One drawback of prior art surgical knife blades and methods for making sutureless incisions in the eye is that separate knife blades must be utilized to form an initial incision and a subsurface pocket, respectively. Another drawback of prior art surgical knife blades and methods for forming sutureless incisions in the eye is that there is no way to gauge the optimal distance from an anatomical reference for the site of the initial incision. Additionally, prior art surgical knife blades and methods of making sutureless incisions in the eye do not allow the extent of commitment into the sclera and clear cornea to be precisely judged prior to entering the anterior chamber such that the subsurface pocket cannot be controllably extended into the cornea to allow the anterior chamber to be entered therefrom. A further disadvantage of prior art surgical knife blades and methods of making sutureless incisions in the eye is that the subsurface pocket cannot be made in its entirety in the cornea, where indicated, allowing the initial incision to be made at the limbus.